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Amylopectins

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Eric Bertoft – 1st expert on this subject based on the ideXlab platform

  • Observations on the impact of amylopectin and amylose structure on the swelling of starch granules
    Food Hydrocolloids, 2020
    Co-Authors: Varatharajan Vamadevan, Eric Bertoft

    Abstract:

    Abstract Four different types of amylopectin structure have been reported in our earlier work based on the internal unit chain profile obtained from limit dextrins of amylopectin and data strongly suggested that chain length and organization of internal unit chains of amylopectin influence the gelatinization and retrogradation properties of the starch. Another important functional attribute is granule swelling that mainly contributes to the viscosifying property of starches. In this study, unmodified defatted amylose-containing starch granules possessing amylopectin of four types were subjected to swelling in warm water. The swelling pattern of the granules was related to the structural type of the amylopectin component. Granules having amylopectin of Type 1 structure started to swell at lower temperature (about 55 °C) and possessed more restricted swelling than most of the other starches. Type 1 starches lost their integrity at temperatures above 85 °C, whereas starch granules with Type 2 and 3 amylopectin were still intact at 95 °C. Starches with Type 4 amylopectin were heterogeneous with respect to their swelling: Lesser yam starch possessed comparatively restricted swelling between 75 and 95 °C, whereas canna and potato starch swelled extensively and disintegrated already before 95 °C. Some waxy samples were also included in the investigation and these were generally more sensitive to swelling than their non-waxy counterparts, showing that amylose restricts the swelling and stabilizes the granular structure, albeit there was no correlation between the apparent amylose content and the swelling of tested samples. Instead, the result suggested a correlation between the structure of amylopectin and the deposition of amylose in the starch granules.

  • Impact of different structural types of amylopectin on retrogradation
    Food Hydrocolloids, 2018
    Co-Authors: Varatharajan Vamadevan, Eric Bertoft

    Abstract:

    Abstract Retrogradation is the re-association and recrystallization process of glucan chains in gelatinized starch. The objective of the study was to investigate the effect of amylopectin structure on re-association of glucan chains during retrogradation. Amylopectin retrogradation of 17 starches from four different structural types was examined by differential scanning calorimetry (DSC). Gelatinized starches were stored for 10 days at 4 °C and then scanned from 10–120 °C at 10 °C/min. The structural type of amylopectin influenced the transition temperatures (Tm and Tc), melting temperature range (Tc–To) and enthalpy change of transition (ΔH). Correlation analysis between different chain length categories and the melting parameters of recrystallized amylopectin revealed a strong correlation of the external chain length (ECL) with Tm (r = 0.90, p

  • Fine Structure of Amylopectin
    Starch, 2015
    Co-Authors: Eric Bertoft

    Abstract:

    Starch granules consist of two major polyglucans, namely, branched amylopectin and essentially linear amylose. In all nonmutant starches, amylopectin is the major component and is responsible for the internal structure of starch granules, which is the native, semicrystalline form of starch. The granules, irrespective of the plant source, consist of granular rings of alternating amorphous and semicrystalline polymers. On a smaller scale, blocklets as well as crystalline and amorphous lamellae have been identified. Amylopectin is generally accepted as the contributor to the lamellar structure, but the nature of blocklets is only beginning to be resolved. Amylopectin consists of numerous chains of glucosyl units that are divided into short and long chains. These chains are organized as clusters that have been isolated by using endo-acting enzymes, and the fine structure of the clusters have been investigated. The clusters consist of still smaller, tightly branched units known as building blocks. The organization of the clusters and building blocks in the macromolecular structure of amylopectin is to date uncertain, and two schools exist at present suggesting that amylopectin either has a treelike branched cluster structure or a building block backbone structure. The structural features of amylopectin and the two models presently in debate are discussed in this chapter.

M Van Bruijnsvoort – 2nd expert on this subject based on the ideXlab platform

  • retention behaviour of Amylopectins in asymmetrical flow field flow fractionation studied by multi angle light scattering detection
    Journal of Chromatography A, 2001
    Co-Authors: M Van Bruijnsvoort, Karlgustav Wahlund, Gunilla S Nilsson

    Abstract:

    Abstract Asymmetrical flow field-flow fractionation (FFF) with multi-angle light scattering (MALS) detection was applied for the fractionation of Amylopectins from four different sources. Samples originated from genetically modified potatoes and waxy maize. Amylopectins were dissolved in a 1 mol l −1 sodium hydroxide solution or water. With an injected mass of 0.2 μg, well below overloading conditions, a decrease of the apparent hydrodynamic radius with increasing inlet flow-rate was observed. Moreover, a decrease of the radius of gyration with increasing elution volume was recorded by the MALS detector. Steric/hyperlayer effects are a feasible explanation for this behaviour. The observed radius of gyration at the steric inversion point was in the order of 0.3 μm, which is smaller than the theoretically calculated inversion point. Apparently, the amylopectin behave as macromolecules with a larger hydrodynamic radius than expected on basis of their radius of gyration and are subjected to significant lift forces. The results were confirmed by four fractionations with varying flow-rates but constant ratio of cross to outlet-flow. In contrast to the normal mode operation, the retention of the Amylopectins depended strongly on the applied flow-rates and was close to that of a much smaller 10 kDa dextran. Apparent molar masses in the order of between 10 7 and 10 9 g mol −1 were obtained. The results are contrasted with enzymatically degraded and oxidised starch samples that were fractionated in the normal mode.

Veronique Planchot – 3rd expert on this subject based on the ideXlab platform

  • branching features of Amylopectins and glycogen determined by asymmetrical flow field flow fractionation coupled with multiangle laser light scattering
    Biomacromolecules, 2007
    Co-Authors: Agnes Rollandsabate, Paul Colonna, Maria Guadalupe Mendezmontealvo, Veronique Planchot

    Abstract:

    The aim of this work was to characterize starch polysaccharides using asymmetrical flow field flow fractionation coupled with multiangle laser light scattering. Amylopectins from eight different botanical sources and rabbit liver glycogen were studied. Amylopectins and glycogen were completely solubilized and analyzed, and high mass recoveries were achieved (81.7−100.0%). Amylopectin Mw, RG, and the hydrodynamic coefficient νG (the slope of the log−log plot of RGi vs Mi) were within the ranges 1.05−3.18 × 108 g mol-1, 163−229 nm, 0.37−0.49, respectively. The data were also considered in terms of structural parameters. The results were analyzed by comparison with the theory of hyperbranched polymers (Flory, P. J. Principles of Polymer Chemistry; Cornell University Press:  Ithaca, NY, 1953; Burchard, W. Macromolecules, 1977, 10, 919−927). This theory, based upon the ABC model, has been shown to underestimate the branching degrees of Amylopectins. However, quantitative agreement with the data in the litera…